3-dimensional curved substrate lamination

ABSTRACT

A method of laminating a surface of a flexible material to a surface of a rigid, curved material. The method includes pressing an area of the surface of the flexible material into the surface of the rigid, curved material with a holder to create a contact area while the flexible material is conformed to the holder, which has a curvature greater than a curvature of the rigid, curved material surface; and changing the contact area between the surface of the flexible material and the surface of the rigid, curved material while maintaining pressure on the contact area until the surface of the flexible material and the surface of the rigid curved material are laminated.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/237,281, filed on Sep. 24, 2008, which claims priority to U.S.Provisional Patent Application Nos. 61/126,864 filed on May 7, 2008 and61/078,325 filed on Jul. 3, 2008, the entire disclosures of which areincorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to lamination of flexible or rigid materials, andmore particularly, to lamination of materials to a curved, rigidsubstrate.

BACKGROUND OF THE INVENTION

Conventional lamination processes are adequate for laminating asubstantially flat/planar material to a substantially flat/planarsubstrate. For example, in the field of electronic devices, manyconventional methods exist to laminate a planar printed circuit board toa planar substrate, such as another planar printed circuit board, toform a single, laminated circuit board. However, conventional techniquesmay not work when the substrate is substantially curved.

SUMMARY OF THE INVENTION

Laminating a flexible material to a curved substrate can pose severaldifficulties, particularly when the process is applied in the field ofelectronic devices. For example, it may be more difficult to prevent airbubbles from getting trapped between a flexible material and a curvedsubstrate during lamination than between rigid straight material. Insome electronics applications, for example, laminates must meet strictquality requirements that limit the number and/or size of trapped airbubbles. If a laminate has too many trapped air bubbles, or if the airbubbles are too large, the laminate must often be discarded asdefective, resulting in lost time and money. Even if the adhesive usedin the defective laminate can be reworked to reduce trapped bubbles, there-lamination process would still result in lost time. In addition, thematerials used in the laminates of some electronic devices can berelatively delicate. This limits the maximum pressure that can beapplied during lamination.

In one embodiment of the invention, a lamination system includes a baseand an upper portion. The base includes a lower holder. The upperportion includes an upper holder and control circuitry. The lower holderincludes a lower contact surface that is placed in contact with anon-lamination surface of a substrate, such as the non-laminationsurface of the substrate. The upper holder includes an upper contactsurface that is placed in contact with a non-lamination surface of aflexible material, such as the non-lamination surface of the flexiblematerial. The lower holder and the upper holder may each be mounted to amotion block. The lower and upper motion blocks can provide varioustypes of motion to the holders ranging from single axis motion to fullyarticulated motion, depending on the requirement of the particularlamination system. Different embodiments of the disclosed laminationsystem are described in more detail below.

During the lamination process, the lamination surfaces are broughttogether with an adhesive material in between. Various types ofadhesives can be used, including pressure-sensitive adhesives (PSAs),re-workable PSAs, thermoplastic film, thermoset film, thermal cureliquid (single or multiple components), ultraviolet (UV) cure liquid,and multiple-component adhesives that cure at room temperature. Theadhesive(s) may be applied to the substrate, the flexible material, orboth. In addition, the adhesive(s) may be applied as a sheet or sheets,and/or one or more regions of liquid adhesive. As the laminationsurfaces are brought into contact, a force-applying area of the uppercontact surface and a force-applying area of the lower contact surfaceapply opposing forces to press together the substrate and the flexiblematerial in a pressure region between the upper and lower force-applyingareas. The portions of the substrate and the flexible material in thepressure region are pressed together and laminated with the adhesivematerial. Either or both of the lower holder and the upper holder may beheated to improve adhesive properties. Lamination may also be performedat or below room temperature.

In another embodiment, a lower holder is a base chuck formed of a rigidmaterial, such as glass or a metal. The lower holder has a lower contactsurface that is shaped to conform to a non-lamination surface of acurved substrate. An upper holder is a vacuum chuck formed of acompliant material, such as rubber. The upper holder has an uppercontact surface with vacuum holes (not shown) to hold a non-laminationsurface of a flexible printed circuit board (PCB) in place on the uppercontact surface. Thus, flexible PCB is forced into the shape of uppercontact surface. In one embodiment, the upper contact surface initiallyhas a higher curvature than the lower contact surface.

During an early stage of a lamination process, the upper holder is movedalong a z-axis direction towards the lower holder, causing a laminationsurface of flexible PCB to contact a lamination surface of curvedsubstrate initially at a single-point, causing the lamination surfacesto be pressed together in a pressure region between force-applying areasof the upper contact surface and the lower contact surface,respectively. As the lamination process continues, the upper holder ispressed further in the z-direction, against the lower holder. Theincreasing pressure causes the size of the pressure region to growlarger.

During a latter part of the lamination process, after upper holder hasbeen moved further along the z-axis towards lower holder. Because upperholder is made of a compliant material, the motion has caused the upperholder to deform. Now, the contact area between the lamination surfaceof the PCB and the lamination surface of the curved substrate becomesgreater than it was during the early stage of the lamination process.The larger contact area causes the lamination surfaces to be pressedagainst each other in a larger pressure region between largerforce-applying areas of the upper contact surface and the lower contactsurface, respectively. In this embodiment, the process continues untilthe pressure region expands to cover the entire lamination surfaces.

Because the pressure region begins as a single point and expands fromthat point during the lamination process, surrounding air may be lesslikely to become trapped between the flexible PCB and curved substrateas a result of air being pushed out and away from the center as theprocess continues. Therefore, the lamination system according to thisembodiment may potentially reduce or eliminate the formation of airbubbles caused during lamination. In addition, because the upper holderis formed of a compliant material, the present example embodiment may bebetter-suited for lamination of relatively delicate materials.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates examples of a curved substrate and a flexiblematerial according to embodiments of the invention.

FIG. 1B illustrates the curved substrate and the flexible material ofFIG. 1A laminated together according to embodiments of the invention.

FIGS. 2A and 2B are cross-sectional views showing details of thecurvature of the substrate in the y-direction and the x-direction,respectively, according to embodiments of the invention.

FIG. 3 is a more detailed, cross-sectional view of a portion of theflexible material according to embodiments of the invention.

FIG. 4A illustrates an exemplary curved surface for a sensor arrayaccording to embodiments of this invention.

FIG. 4B illustrates an exemplary “butterfly” pattern for a sensor arrayaccording to embodiments of this invention.

FIG. 4C illustrates an exemplary two-strip sensor array patternaccording to embodiments of this invention.

FIG. 4D illustrates an exemplary three-strip sensor array patternaccording to embodiments of this invention.

FIG. 4E illustrates an exemplary flat sensor pattern in a “snail”pattern that can be applied to a curved surface according to embodimentsof this invention.

FIG. 5 illustrates an exemplary lamination system according toembodiments of the invention.

FIGS. 6-8 are cross-sectional views illustrating the operation of alower holder and an upper holder of an exemplary lamination systemaccording to embodiments of the invention.

FIGS. 9A and 9B are cross-sectional views illustrating the operation ofa lower holder and an upper holder of another exemplary laminationsystem according to embodiments of the invention.

FIGS. 10A-C are cross-sectional views illustrating the operation of alower holder and an upper holder of another exemplary lamination systemaccording to embodiments of the invention.

FIGS. 11A and 11B illustrate the operation of a lower holder and anupper holder of another exemplary lamination system according toembodiments of the invention.

FIGS. 12A-E each shows three top views taken along the z-axis of thesubstrate at progressively increasing times during the second stage toillustrate various ways in which pressure region can change depending onthe different configurations of the lamination system according toembodiments of the invention.

FIGS. 13A and 13B illustrate a substrate and flexible material withmulti-axis curvatures according to embodiments of the invention.

FIGS. 14A-D illustrate the operation of a lower holder and an upperholder of another exemplary lamination system according to embodimentsof the invention.

FIG. 15 illustrates the operation of an upper holder of anotherexemplary lamination system according to embodiments of the invention.

FIGS. 16-18 illustrate the operation of a lower holder and an upperholder of another exemplary lamination system according to embodimentsof the invention.

FIGS. 19-21 illustrate the operation of a lower holder and an upperholder of yet another exemplary lamination system according toembodiments of the invention.

FIG. 22 illustrates the operation of a lower holder and an upper holderof yet another exemplary lamination system according to embodiments ofthe invention.

FIGS. 23A-B, 24A-C, and 25 illustrate various exemplary alignmentstructures that can be used to help align a flexible material accordingto embodiments of the invention.

FIG. 26 is a perspective view illustrating a 2-step process forlaminating a printed circuit board (PCB) to a curved substrate accordingto embodiments of the invention.

FIG. 27 is a perspective view illustrating a 1-step process forlaminating a PCB to a curved substrate.

FIGS. 28A-C illustrates the operation of a lower holder and an upperholder of another example lamination system according to embodiments ofthe invention.

FIGS. 29A-B illustrate a post-lamination device and process according toembodiments of the invention.

FIG. 30 illustrates a perforated substrate according to embodiments ofthis invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following description of preferred embodiments, reference is madeto the accompanying drawings, in which it is shown by way ofillustration specific embodiments in which the invention can bepracticed. It is to be understood that other embodiments can be used andstructural changes can be made without departing from the scope of theembodiments of this invention.

For the sake of clarity, many of the figures do not show an adhesiveused in the lamination processes described below. However, it isunderstood that an adhesive or other approach that allows the fixingtogether of two materials may be used in these processes.

The present disclosure relates to apparatus and methods for laminating arigid or flexible material to a curved substrate.

FIGS. 1A and 1B are perspective drawings illustrating examples of acurved substrate 101 and a flexible material 103 that may be laminatedtogether according to embodiments of the invention. In particular, FIG.1A shows the substrate 101 and the flexible material 103 beforelamination. As illustrated, the substrate 101 and the flexible material103 have lamination surfaces 105 and 107, respectively, adapted to belaminated together. The substrate 101 and the flexible material 103 alsohave non-lamination surfaces 109 and 111, respectively, that areopposite the lamination surfaces. In this embodiment, the substrate 101may be a glass plate that is curved along more than one axis, i.e.,multi-axis curvature. Other substrates suitable for lamination mayinclude plastics, ceramics, and other materials. As illustrated in FIG.1A, substrate 101 is curved in both the x-axis and the y-axis. A closerview of the curvature of substrate 101 is provided in FIGS. 2A and 2B.

FIG. 1B shows the substrate 101 and the flexible material 103 havingtheir respective lamination surfaces (not shown) fixed together as aresult of the lamination process.

FIGS. 2A and 2B are cross-sectional views showing details of thecurvature of the substrate 101 in the y-direction and the x-direction,respectively. The degree of curvature in each axis may or may not be thesame. In this embodiment, the figures show that the curvature of thesubstrate 101 along the y-axis is generally greater than the curvaturealong the x-axis. In addition, the curvature of the substrate 101 canvary along an axis. For example, FIG. 2A shows a portion 201 nearer toan edge of the substrate 101 along the y-axis and a portion 203 nearerto the center of the substrate 101 along the y-axis. Portions 201 and203 are magnified to illustrate that the curvature of portion 201 isgreater than the curvature of portion 203. In other words, the substrate101 is straighter near its center than at its edges.

Referring again to FIG. 1A, in this embodiment, flexible material 103 isa substantially planar circuit board. In particular, the circuit boardis formed by, for example, depositing circuit elements, such asresistors, capacitors, transistors, and/or conductive traces (e.g.,wires) onto a flexible board substrate. An insulating layer can bedeposited over the circuit elements to protect against environmentalelements such as moisture, as well as to provide a smoother surface forlamination. However, the surface of the insulating material may not beperfectly smooth. In other embodiments, the flexible material 103 may bean optically transparent material, such as a plastic with patternedindium tin oxide (ITO).

FIG. 3 is a more detailed, cross-sectional view of a portion of theflexible material 103. FIG. 3 shows conductive traces 301 on a flexibleboard substrate 303, and an insulating layer 305 deposited over theconductive traces 301. Because the conductive traces 301 protrude fromthe surface of the board substrate 303, the surface of the insulatinglayer 305 has “peaks” 307 over the conductive traces 301 and “valleys”309 between the conductive traces 301. Therefore, the surface insulatinglayer 305, which is the lamination surface 307 in this embodiment, isnot perfectly smooth.

The flexible material 103 need not be a continuous sheet, and may havecutouts, slits, or other characteristics that allow the flexiblematerial 103 to be conformed to a curved surface. FIGS. 4A-4Eillustrates various forms of the flexible materials 103, such asflexible circuit boards, and curved surfaces.

FIG. 4A illustrates an exemplary curved surface for a sensor arrayaccording to embodiments of this invention. A typical flex circuitsensor array applied to the inside of this surface may tend to wrinkle,buckle, or snap.

FIG. 4B illustrates an exemplary “butterfly” pattern for a sensor arrayaccording to another embodiment of the invention. This pattern can beformed using a flat array and applied to a curved surface withoutwrinkling.

FIG. 4C illustrates an exemplary two strip sensor array patternaccording to yet another embodiment of this invention.

FIG. 4D illustrates an exemplary three strip sensor array patternaccording to yet another embodiment of this invention. Both patternsshown in FIGS. 4C and 4D can also be formed from a flat array andapplied to a curved surface.

FIG. 4E illustrates an exemplary flat sensor pattern in a “snail”pattern that can be applied to a curved surface according to yet anotherembodiment of this invention.

The above-described curved or three-dimensional shaped sensor patternsin FIGS. 4A-4E may be placed under or over a curved substrate, forexample, a glass or plastic cover. These sensors patterns can be used ina variety of multi-touch devices, for example a multi-touch mouse.

In another embodiment, the sensor array can be formed on a thermalplastic substrate material that can be reformed with heat. In thisconfiguration the sensor array may be draped across a mold and thenheated to form a curved sensor array shape. Alternatively, the substratemay be vacuum formed inside a cavity. The traces in the array, which mayfor example be made out of copper, may be made flexible enough towithstand this type of reshaping.

Laminating a flexible material to a curved substrate can pose severaldifficulties, particularly when the process is applied in the field ofelectronic devices. For example, it may be more difficult to prevent airbubbles from getting trapped between a flexible material and a curvedsubstrate during lamination than between rigid straight material. Insome electronics applications, for example, laminates must meet strictquality requirements that limit the number and/or size of trapped airbubbles. If a laminate has too many trapped air bubbles, or if the airbubbles are too large, the laminate must often be discarded asdefective, resulting in lost time and money. Even if the adhesive usedin the defective laminate can be reworked to reduce trapped bubbles, there-lamination process would still result in lost time.

In addition, the materials used in the laminates of some electronicdevices can be relatively delicate. This limits the maximum pressurethat can be applied during lamination. For instance, the substrate 101in FIG. 1A may be glass, which is breakable under pressure. Similarly,the flexible material 103 in FIG. 1A may be a circuit board that canonly sustain a limited amount of pressure to prevent damages to itscircuit elements.

In view of the foregoing, FIG. 5 illustrates a lamination system 500according to an embodiment of the invention. Lamination system 500includes a base 503 and an upper portion 507. The base 503 includes alower holder 505. The upper portion 507 includes an upper holder 509 andcontrol circuitry 511. The lower holder 505 includes a lower contactsurface 513 that is placed in contact with a non-lamination surface of asubstrate, such as the non-lamination surface 109 of the substrate 101in FIG. 1A. The upper holder 509 includes an upper contact surface 515that is placed in contact with a non-lamination surface of a flexiblematerial, such as the non-lamination surface 111 of the flexiblematerial 103 of FIG. 1A. The lower holder 505 and the upper holder 509may each be mounted to a motion block 517, 519. The lower and uppermotion blocks 517, 519 can provide various types of motion to theholders ranging from single axis motion to fully articulated motion,depending on the requirement of the particular lamination system.Different embodiments of the disclosed lamination system are describedin more detail below.

During the lamination process, the lamination surfaces are broughttogether with an adhesive material in between. Various types ofadhesives can be used, including pressure-sensitive adhesives (PSAs),re-workable PSAs, thermoplastic film, thermoset film, thermal cureliquid (single or multiple components), ultraviolet (UV) cure liquid,and multiple-component adhesives that cure at room temperature. Theadhesive(s) may be applied to the substrate, the flexible material, orboth. In addition, the adhesive(s) may be applied as a sheet or sheets,and/or one or more regions of liquid adhesive. As the laminationsurfaces are brought into contact, a force-applying area of the uppercontact surface 515 and a force-applying area of the lower contactsurface 513 apply opposing forces to press together the substrate andthe flexible material in a pressure region between the upper and lowerforce-applying areas. The portions of the substrate and the flexiblematerial in the pressure region are pressed together and laminated withthe adhesive material. Either or both of the lower holder 505 and theupper holder 509 may be heated to improve adhesive properties.Lamination may also be performed at or below room temperature.

As described in more detail in the following exemplary embodiments, theupper holder 509 and the lower holder 505 may be formed such that thepressure region may change during the lamination process. For example,in some embodiments, the pressure region changes in position during thelamination process. In other embodiments, the pressure region changes insize and/or shape during the lamination process. In still otherembodiments, the pressure region changes in position and in size/shapeduring the lamination process. In yet other embodiments, the shape andposition of the pressure region remain the same. By changing position,size, shape, and/or other aspects of the pressure region, problems suchas the formation of trapped air bubbles may be minimized.

FIGS. 6-8 are cross-sectional views illustrating the operation of alower holder and an upper holder of an embodiment of the disclosedlamination system. Referring to FIG. 6, a lower holder 601 is a basechuck formed of a rigid material, such as glass or a metal. Lower holder601 has a lower contact surface 603 that is shaped to conform to anon-lamination surface 605 of a curved substrate 607. An upper holder609 is a vacuum chuck formed of a compliant material, such as rubber.The upper holder 609 has an upper contact surface 611 with vacuum holes(not shown) to hold a non-lamination surface 613 of a flexible printedcircuit board (PCB) 615 in place on the upper contact surface 611. Thus,flexible PCB 615 is forced into the shape of upper contact surface 611.As shown in FIG. 6, the upper contact surface 611 initially has a highercurvature than the lower contact surface 603.

FIG. 7 shows lower holder 601 and upper holder 609 during an early stageof a lamination process. Specifically, the upper holder 609 is movedalong a z-axis direction towards the lower holder 601, causing alamination surface 701 of flexible PCB 615 to contact a laminationsurface 703 of curved substrate 607 initially at a single-point, causingthe lamination surfaces 701 and 703 to be pressed together in a pressureregion 705 between force-applying areas 707 and 709 of the upper contactsurface 611 and the lower contact surface 603, respectively.

As the lamination process continues, the upper holder 609 is pressedfurther in the z-direction, against the lower holder 601. The increasingpressure causes the size of the pressure region 705 to grow larger.

FIG. 8 shows the lower holder 601 and the upper holder 609 during alatter part of the lamination process, after upper holder 609 has beenmoved further along the z-axis towards lower holder 601. Because upperholder 609 is made of a compliant material, the motion has caused theupper holder 609 to deform. Now, the contact area between the laminationsurface 701 of the PCB 615 and the lamination surface 703 of the curvedsubstrate 607 becomes greater than it was during the early stage of thelamination process shown in FIG. 7. The larger contact area causes thelamination surfaces 701, 703 to be pressed against each other in alarger pressure region 801 between larger force-applying areas 803 and805 of the upper contact surface 611 and the lower contact surface 603,respectively. In this embodiment, the process continues until thepressure region expands to cover the entire lamination surfaces 701,703.

Because the pressure region begins as a single point and expands fromthat point during the lamination process, surrounding air may be lesslikely to become trapped between the flexible PCB 615 and curvedsubstrate 607 as a result of air being pushed out and away from thecenter as the process continues. Therefore, the lamination systemaccording to this embodiment may potentially reduce or eliminate theformation of air bubbles caused during lamination. In addition, becausethe upper holder 609 is formed of a compliant material, the presentexample embodiment may be better-suited for lamination of relativelydelicate materials.

FIGS. 9A and 9B are cross-sectional views illustrating the operation ofa lower holder and an upper holder of another exemplary laminationsystem according to embodiments of the invention. The system of FIGS. 9Aand 9B is similar to the system of FIGS. 6-8. Referring to FIG. 9A, thesystem includes a base 901 including a lower holder 903 with a lowercontact surface 905. The system also includes an upper portion, press907, having an upper holder 909 with an upper contact surface 911. Onedifference between this embodiment (illustrated in FIGS. 9A and 9B) andthe previous embodiment (illustrated in FIGS. 6-8) is that, in thissystem, the upper holder 909 is a rigid chuck and the lower holder 903is of deformable, compliant material, such as rubber. Also, the systemillustrated in FIGS. 9A and 9B includes retractable alignment pins 913protruding from the lower holder 903, and vacuum holes 915 through boththe upper and lower holders 909, 903.

In this system, a curved substrate 917 is fixed to upper contact surface911 by positioning the substrate over vacuum holes 915 and applying avacuum to the holes. A flexible PCB 919 is fixed to the lower holder 903by using the vacuum holes 915 through the lower holder 903. Theretractable alignment pins 913 provide a guide when positioning andfixing the flexible PCB 919 onto the lower holder 903. The vacuum holes915 keeps the flexible PCB 919 warped over the lower holder 903 beforelamination.

FIG. 9B illustrates the system of FIG. 9A during a lamination process.As in the embodiment described above, the upper holder 909 is movedalong a z-axis direction towards the lower holder 903 so that therespective lamination surface of the curved substrate 917 and theflexible PCB 919 are pressed together at a pressure region that beginsat a contact point 991 because the curvature of the lower holder 903 ishigher than the upper holder 909. The pressure region expands as theupper holder 909 continues to be pressed against the lower holder 903because the lower holder 903 is made of a compliant, deformable materialand deforms as it receives increasing pressure. As the pressure regionexpands, the retractable alignment pins 913 may be retracted and thelamination surface of the curved substrate 917 can eventually be incontact with the entire area of the lamination surface of the PCB 919.Alternately, lower holder 903 may be moved toward upper holder 909 inthe z-axis direction to achieve the same lamination result.

FIGS. 10A-C are cross-sectional views illustrating the operation of alower holder and an upper holder of another exemplary lamination systemaccording to embodiments of this invention. The system of FIGS. 10A-C issimilar to the system illustrated in FIGS. 9A and 9B. Referring to FIG.10A, the system includes a base 1002 including a lower holder 1004 witha lower contact surface 1006. A bottom substrate 1016 is held by thelower holder 1004 by a vacuum chuck (not shown) or mechanical featuresof the lower holder 1004. The system also includes an upper portion, forexample, a press 1008. The upper portion includes an upper holder 1010.In this embodiment, the upper holder 1010 has a flexible membrane 1012adapted to hold a top substrate 1014 in a pre-form position. In variousembodiments, the top substrate 1014 may be held by a vacuum chuck (notshown) or other mechanical features of the upper holder 1010. Themembrane 1012 may be a conformal material (e.g., silicone rubber) or aliquid or air filled sac.

FIGS. 10B and 10C illustrate the system of FIG. 10A during a laminationprocess. Referring to FIG. 10B, similar to previously disclosedembodiments, the upper holder 1010 is moved towards the lower holder1004 so that the bottom surface of the top substrate 1014 becomes incontact with and presses against the top surface of the bottom substrate1016. Because the curvature of the lower holder 1004 is less than thecurvature of the upper holder 1010, the initial contact between the topsubstrate 1014 and the bottom substrate 1016 is made at the center ofthe top surface of the bottom substrate 1016, as a result of themovement of the upper holder 1008 towards the lower holder 1004 in thez-direction.

FIG. 10C illustrates the next stage in the lamination process. As theupper holder 1010 continues to exert pressure on the lower holder 1004after the initial contact between the top substrate 1014 and the bottomsubstrate 1016, the flexible membrane 1012 of the top holder starts todeform. As a result, the initial pressure point expands from the centerof the top surface of the bottom substrate 1016 towards the edges of thebottom substrate 1016 until the top substrate 1014 and the bottomsubstrate 1016 are completely laminated to each other, as illustrated inFIG. 10C. Because the upper holder 1010 includes a flexible membrane1012 in this embodiment, pressure is applied evenly in all directionsagainst the bottom substrate 1016 in the lamination process. The upperholder 1010 may also be made of other types of material that allows itto apply pressure evenly in all directions in the lamination process.Either or both of the lower holder 1004 and the upper holder 1010 may beheated to improve adhesive properties. In various embodiments, theprocess illustrated in FIGS. 10A-C can be applied in a reverse setup byrotating the illustrated system 180 degrees so that the lower holder ison top and the upper holder is at the bottom.

FIGS. 11A and 11B illustrate the operation of a lower holder and anupper holder of another exemplary lamination system according toembodiments of the invention. In this system, a curved substrate 1101 isplaced on a lower holder 1103 that includes fixed alignment pins 1105. Aflexible material 1109 is secured over the lower holder 1103 by placingthe alignment holes 1107 on the flexible material 1109 over thealignment pins 1105. FIG. 11A illustrates a first stage of a laminationoperation in which an upper holder 1111 is moved along the z-axistowards the lower holder 1103. The upper holder 1111 is mounted to theupper motion block 519 of FIG. 5 by a motion articulator such as agimbal 1113 (other articulators could include ball joints, hinges orother mechanical linkage) to provide articulated motion includingtranslational and rotational motion along multiple axes. As the upperholder 1111 approaches the lower holder 1103, a leading portion 1115 ofthe upper holder 1111 contacts a first area 1117 of flexible material1109 and pushes the area 1117 towards the substrate 1101. In variousembodiments, the initial contact between the leading portion 1115 andthe first area 1117 of the flexible material may be at different angles.The upper holder 1111 continues moving along the z-axis until theleading portion 1115 causes the first area 1117 of the flexible material1109 to contact a first area 1119 of the substrate 1101, creating apressure region (not shown).

FIG. 11B illustrates a second stage of the lamination operation. Thesecond stage begins after the first area 1117 of flexible material 1109contacts the first area 1119 of the substrate 1101. In the second stage,the upper holder 1111 rotates about the y-axis until the top flatsurface 1110 of the upper holder 1111 is parallel to the bottom flatsurface 1120 of the lower holder as the upper holder 1111 moves towardsthe lower holder 1103 along the z-axis. This second stage motion causesthe pressure region 1121 to change in size, shape, and/or position. Howthe pressure region 1121 changes may depend on several factors, such asthe shapes and rigidity of the upper and lower holders 1111, 1103, thetype and amount of force/motion applied through the gimbal 1113 duringoperation, and other factors.

FIGS. 12A-E each shows three top views taken along the z-axis atprogressively increasing times during the second stage to illustrate thevarious ways in which the pressure region 1121 evolves depending on thedifferent configurations that will now be described. In the figures, theshaded areas represent pressure region 1121. The views are taken attimes t=0 (beginning of second stage, initial contact of first area 1117and first area 1119), t=1 (approximately midway through second stage),and t=2 (approximately the end of the second stage).

Referring to FIG. 12A, if both holders are formed of rigid materials andhave constant, single-axis curvature (i.e., cylindrical curvature asshown in FIGS. 11A and 11B), the curvature of upper holder 1111 isgreater than the curvature of lower holder 1103, and an even force isapplied through the gimbal such that upper holder 1111 rolls acrosslower holder 1103 and applies a constant pressure during the secondstage, then the size and shape of pressure region 1121 will remainsubstantially constant, but the position of pressure region 1121 willmove along the lamination surfaces as shown in FIG. 12A.

Referring to FIG. 12B, if the configuration is the same as in FIG. 12A,except that the curvature of upper holder 1111 is the same as thecurvature of lower holder 1103, the size of pressure region 1121 willincrease, but the type of shape will remain roughly rectangular. Asillustrated, in this embodiment, the aspect ratio of the rectangularshape will change. The position of one side 1210 of the rectangle willremain substantially fixed while the position of the opposite side 1212will move farther away as shown in FIG. 12B.

Referring to FIG. 12C, the configuration of the lamination system is thesame as in FIG. 12A, except that one or both of the holders is formed ofa compliant material and the force along the z-axis towards the lowerholder 1103 is constantly increased through gimbal 1113 during the firsthalf of the second stage and then constantly decreased during the lasthalf of the second stage. As the result, the size of pressure region1121 will increase in the first half of the second stage and decrease inthe last half of the second stage, the shape of the pressure region 1121remains rectangular though the aspect ratio will change, and theposition will move along the lamination surfaces as shown in FIG. 12C.

Referring to FIG. 12D, the configuration of the lamination system usedhere is the same as in FIG. 12A, except that both holders have constant,multi-axis curvature (e.g., curvature along the x-axis and the y-axis asshown in FIGS. 13A and 13B), and the upper holder 1111 has greatercurvature than the lower holder 1101 in both axes. As the result, thesize and shape of the pressure region 1121 remains fairly constantthroughout the second stage and the position of the pressure region 1121may change as shown in FIG. 12D.

As is apparent in FIG. 12D, the entire area of the lamination surfacesmay not be exposed to the pressure region 1121 in the single pass ofupper holder 1111. This is different from the configurations of FIGS.12A-12C which covers the entire lamination surfaces in a single pass.Therefore, it may be desirable to drive the upper holder 1111 throughadditional motion to cover the entire lamination surface. For example,the gimbal 1113 could provide an additional rotation motion around thex-axis to roll the upper holder 1111 to one side, and then provide amotion substantially reverse of the previous motion, resulting in thepressure region changes shown in FIG. 12E.

In all the configurations described above, the substrate curvature isnot limited to single axis (cylindrical curvature). Arbitrary multi-axiscurvature may be supported by any of these configurations. FIG. 13Ashows a variation of the lamination system of FIG. 11A. As illustrated,both the upper holder 1302 and the lower holder 1308 have contactsurfaces 1310, 1312 that have multi-axis curvature. In variousembodiments, the curvature of the upper contact surface 1310 may or maynot be the same as the curvature of the lower contact surface 1312. Asillustrated in FIG. 13B, the curved substrate 1306 is fixed to the lowerholder 1308 and substantially adapts the curvature of the lower contactsurface 1312 of the lower holder 1308. Similarly, the flexible material1304 may conform to the curvature of the upper contact surface 1310 ofthe upper holder 1302.

FIGS. 14A-D illustrate the operation of a lower holder and an upperholder in a side-to-side lamination process according to anotherembodiment of the invention. This embodiment shares some of the featuresof the embodiments illustrated in FIGS. 10A-C and FIGS. 11A-B. Referringto FIG. 14A, the system includes a base 1402 including a lower holder1404 with a lower contact surface 1406. A bottom substrate 1416 is heldby the lower holder 1404 by a vacuum chuck (not shown) or mechanicalfeatures of the lower holder 1404. The system also includes an upperportion, for example, a press 1408. The upper portion has affixed to itan upper holder 1410. In this embodiment, the upper holder 1410 has aflexible membrane 1412 adapted to hold a top substrate 1414 in apre-form position. In various embodiments, the top substrate 1414 may beheld by a vacuum chuck (not shown) or other mechanical features of theupper holder 1410. The membrane 1412 may be a conformal material (e.g.,silicone rubber) or a liquid or air filled sac. As illustrated in FIG.14A, prior to the start of the lamination process, the press/upperholder 1408, 1410 and the base/lower holder 1402, 1406 are positionedlike an open book, where the press/upper holder 1408, 1410 is the “bookcover” and the base/lower holder 1402, 1406 is the rest of the book. Thepress 1408 and the base 1402 may or may not be in contact with eachother. Both the top substrate 1414 and the bottom substrate 1416 areheld on top of their respective holders 1410, 1404. The left edge of thepress 1408 is approximately aligned with the right edge of the base 1402so that when the upper holder 1410 rotates counter clockwise about they-axis, the upper substrate 1414 can be in position to make contact withthe bottom substrate 1416 and become laminated to the bottom substrate1416.

Referring to FIG. 14B, as the upper portion rotates about the y-axis, afirst portion 1420 of the upper substrate 1414 initially comes intocontact with a first portion 1422 of the bottom substrate 1416. Apressure region (not shown) is formed at the initial point of contactbetween the first portion 1420 of the upper substrate 1414 and the firstportion 1422 of the bottom substrate 1416. After the initial contact,the upper portion continues to rotate about the y-axis, causing thepressure region to change in size, shape, and/or position. How thepressure region changes can depend on several factors, such as theshapes and rigidity of the upper and lower holders, the type and amountof force/motion applied to by the press during operation, and otherfactors. In various embodiments, the pressure region may change, forexample, as illustrated in FIGS. 12A-12E.

FIG. 14C illustrates a stage in which the side-to-side laminationprocess is at approximately its halfway point where the press 1408 andthe base 1402 are substantially parallel to each other and the upperholder 1410 is in contact and applying pressure to the center region ofthe lower holder 1404. Because the adhesion force between the firstportion 1420 of the upper substrate 1414 and the first portion 1422 ofthe bottom substrate 1416 is higher than the holding force between theupper holder 1410 and the upper substrate 1414, the first area 1420 ofthe upper substrate 1414 in FIG. 14B is now detached from the upperholder 1410 and laminated to the first area 1422 of the bottomsubstrate.

FIG. 14D illustrates the final stage of the side-to-side laminationprocess. As illustrated, the upper portion continues to rotate about they-axis from where it was in FIG. 14C. The center portion of the uppersubstrate 1414 is now detached from the upper holder and laminated tothe center portion of the lower substrate 1416. The pressure region hasshifted beyond the center of the lower holder 1404 and reached the otherside of the lower holder 1410. This allows the upper substrate 1414 tobe completely laminated to the bottom substrate 1422. In thisembodiment, pressure is applied evenly in all directions by the natureof the material that forms the membrane.

The system of FIGS. 14A-D may be overturned and the above describedside-to-side lamination process may be repeated in the oppositedirection to make sure that the substrates are completed laminated andrid of any air bubbles that remains between the substrates.

FIG. 15 illustrates the operation of an upper holder of anotherexemplary lamination system according to embodiments of the invention.In this system, an upper holder 1501 is substantially cylindrical and isformed of a compliant material such as rubber. For the sake of clarity,a lower holder is not illustrated. FIG. 15 also shows a flexiblematerial 1503 held at one end by grippers 1505. The flexible material1503 may include detachable tabs (not shown) to be held by the grippersin some embodiments. During a lamination operation, upper holder 1501rolls across a non-lamination surface 1509 of the flexible material 1503to press the flexible material 1503 and a multi-axis curved substrate1509 together. As upper holder 1501 rolls across flexible material 1503,the upper holder 1501 deforms to conform to the shape of the substrate1509. During the lamination process, the grippers 1505 may, for example,hold a fixed portion of the flexible material 1503, such as an edgeportion or the detachable tabs. In another embodiment, the grippers 1505may slide along the surface of flexible material 1503 while providingenough resistance to reduce slack in the unattached portion of theflexible material 1503.

FIGS. 16-18 illustrate the operation of a lower holder and an upperholder of another exemplary lamination system according to embodimentsof the invention. Referring to FIG. 16, this system includes an upperholder 1601 and a lower holder 1603 that are substantially cylindricalwheels that can rotate about an axis. Note that diameter of one or bothwheels may be chosen based on the curvature of the substrate 1605. Eachholder is formed of a compliant material, such as rubber, foam, aflexible air- or fluid-filled bag, etc. A curved substrate 1605 and aflexible material 1607 are fed in as the holders 1601, 1603 rotate inopposite directions to grab the substrate 1605 and the flexible material1607 and pull them into a working space 1609 between the upper holder1601 and the lower holder 1603. In the working space 1609, the upperholder 1601 and the lower holder 1603 exert opposing forces on theflexible material 1607 and the curved substrate 1605, respectively,which causes the formation of a pressure region 1611 where laminationoccurs. The portion of the flexible material 1607 in the working spaceis forced to be conformed to the upper holder 1601 and, as a result ofthe forces, any air bubbles between the flexible material 1607 and thecurved substrate 1605 are pushed out.

FIG. 17 illustrates a more detailed view of the working space 1609. Inparticular, FIG. 17 shows the opposing force-applying areas 1701 and1703 of flexible material 1701 and substrate 1703, respectively. As seenin FIG. 17, it may be possible to make the pressure region 1611 a smallsize, which may allow for a greater pressure to be applied in thepressure region 1611 while reducing the chance of breakage of thelamination material. This may be particularly useful in the case thatthe lamination materials are delicate, for example, if curved substrate1605 is made of glass. FIG. 18 is a front view illustrating that rollingsurfaces 1801 and 1803 of the upper holder 1601 and the lower holder1603 are deformable and can conform to the shape of the laminatematerials along the y-axis.

FIGS. 19-21 illustrate the operation of a lower holder and an upperholder of another exemplary lamination system according to embodimentsof the invention. Referring to FIG. 19, this system includes an upperholder 1901 that is formed of a hollow, expandable bag or balloon, and alower holder 1903 that is a rigid base. A curved substrate 1905 isplaced on lower holder 1903 with a non-lamination surface of thesubstrate in contact with the lower holder 1903. A flexible material1907 is placed on the curved substrate 1905 with a non-laminationsurface exposed to upper holder 1901. A pump (not shown) is coupled tothe upper holder 1901 to pump, for example, air into and out of theupper holder 1901, so that the upper holder 1901 can be made to expandand contract.

FIG. 20 shows the beginning of a lamination process of the system ofFIG. 19. The upper holder 1901, which is not inflated, is moved alongz-axis towards lower holder 1903 until the surface of upper holder 1901pitch contact with the non-lamination surface of flexible material 1907.Once contact is made, the upper holder 1901 stops moving in the z-axis.The pump (not shown) coupled to the upper holder is turned on to inflatethe upper holder 1901 by pumping air into the upper holder 1901. Asshown in FIG. 21, the shape of the upper holder 1901 changes as itinflates, such that a pressure region is first formed at the point offirst contact and then expands outward in a substantially radialdirection towards the perimeter of the flexible material 1907. This cancause air to be forced from the center to the perimeter of the laminate,helping to eliminate air bubbles in and/or surrounding the pressureregion.

FIG. 22 illustrates the operation of a lower holder and an upper holderof another example lamination system according to embodiments of theinvention. The system shown in FIG. 22 is similar to the system shown inFIGS. 19-21. However, upper holder 1901 is inflated with gas or liquidbefore it is moved into contact with flexible material 1907. Once upperholder 1901 is inflated, it is lowered into contact with flexiblematerial 1907. The motion continues downward after contact, deformingupper holder 1901 and creating a pressure region that increases in sizefrom the initial contact point radially outward towards the perimeter.Note, while the upper holder 1901 is moving downward in contact with theflexible material 1907, air or gas may or may not be pumped into or outof the upper holder 1901. In other words, the degree of inflation of theupper holder 1901 may be increased or decreased while it is moving incontact with the flexible material 1907.

FIGS. 23A-B, 24A-C, and 25 illustrate various example alignmentstructures that can be used to help align a flexible material 2301 whenplacing the flexible material 2301 onto a curved substrate 2303. FIGS.23A-B are perspective views showing the flexible material 2301 formedwith break off tabs 2305 for alignment. In this embodiment, break offtabs 2305 extend from the periphery of the flexible material 2301 andhave holes that can be fit over alignment pins (not shown) to help withalignment. In another embodiment, the holes of break off tabs 2305 canbe used to visually align the flexible material 2301 by matching theholes with fiducials, markers, such as dots or X's (not shown).

FIGS. 24A-C show the alignment holes 2401 in the flexible material 2301that allow for visual alignment of the flexible material 2301 usingfiducials on the substrate 2303. FIGS. 24A and 24B show two differentfull views of the flexible material, and FIG. 24C shows a magnified viewof a hole 2401 aligned with a fiducial 2402 on the substrate 2303.

FIG. 25 shows another layout of alignment holes. As illustrated, thealignment holes 2501 in the flexible material 2301 are an opposite endsof the flexible material 2301.

FIG. 26 is a perspective view illustrating a 2-step process forlaminating a PCB 2605 to a curved substrate 2607, and then laminating astiffener to the PCB back. First, alignment holes 2601 are placed overalignment pins 2603 to align the PCB 2605 with a glass, curved substrate2607. The substrate 2607 is held in position against a base 2609 usingvacuum holes (not shown). In a first step of a lamination process, anupper holder 2611 is moved along the z-axis in the direction towards thebase 2609. After making contact with the PCB 2605, the upper holder 2611continues moving towards the base 2609. This movement causes the PCB2605 to break away from the break away tabs 2613 and become laminatedonto the substrate 2607.

In a second step of the lamination process, a stiffener (not shown) isplaced onto the exposed PCB 2605 surface, and pressed downward by theupper holder 2611 to be laminated to the PCB/glass laminate. Thestiffener may be a rigid material with a curvature that matches thecurvature of the substrate 2607,

FIG. 27 is a perspective view illustrating a 1-step process forlaminating a PCB 2705 to a glass curved substrate 2707, while at thesame time laminating a stiffener 2709 to the PCB back. As in theembodiment shown in FIG. 26, the alignment holes 2701 are placed overalignment pins 2703 to align the PCB 2705 with the glass curvedsubstrate 2707. The substrate 2707 is held in position against a base2711 using vacuum holes (not shown). In this system, the stiffener 2709is held to the upper holder 2713 by, for example, vacuum holes (notshown). In one example embodiment, the stiffener 2709 may be fit into anegative cutout of the upper holder 2713. Therefore, as the upper holder2713 moves downward towards the base 2711, and the upper holder pressesthe PCB 2705 together with substrate 2707, the upper holder 2713 is alsopressing the stiffener 2709 together with the PCB 2705. Therefore, onlya single step (i.e., a single press and release motion) is needed toform a 3-layer laminate of the substrate 2707, the PCB 2705, and thestiffener 2713.

FIGS. 28A-C illustrates the operation of a lower holder and an upperholder of another exemplary lamination system according to embodimentsof the invention. In particular, FIG. 28 is one example of many possiblecombination methods that utilize different features, configurations andprocesses in the previously described embodiments. The system of FIG.28, for example, combines some aspects of the system of FIGS. 6-8 (e.g.,rigid lower holder, upper holder with vacuum holes, lowering upperholder along z-axis to make contact at the center of the lower holderfirst) with some aspects of the system of FIGS. 11, 12, and 13A (e.g.,rigid upper holder, rolling motion of upper holder in y-axis).

Referring to FIG. 28A, an upper holder 2801 having vacuum holes (notshown) that hold a flexible material 2803 is lowered along a z-axis tocontact a rigid curved substrate 2805 at a center contact point. Apressure region 2807 is formed at the center contact point initially andthen moved along the surface of the laminates by applying a rollingmotion of the upper holder 2801. Next, as illustrated in FIG. 28B, asthe rolling motion is applied in one direction, one end 2809 of theflexible material 2803 in the opposite direction begins to buckle and/orseparate from the upper holder 2801. Finally, as illustrated in FIG.28C, the upper holder 2801 rolls in the opposite direction, moving thepressure region 2807 over the buckled portion 2809 of the flexiblematerial 2803 to complete the lamination.

By combining different aspects of embodiments, the pressure regioncausing lamination can be changed in many different ways to achieve thesame lamination result.

FIGS. 29A-B illustrate a post-lamination device and process according toembodiments of the invention. Referring to FIG. 29A, an examplemicrobead surface 2900 is shown. The microbead surface 2900 includes abody 2901 in which a plurality of springs 2903 are positioned. Springs2903 are coupled to microbeads 2905 such that an outward (direction byarrows in FIG. 29A) force is applied to each microbead. The outwardforces of springs 2903 are countered by a plurality of collars (notshown) that hold the microbeads 2900 within the body 2901 while allowinga portion of the microbeads 2905 to protrude from the body 2901. Thus,the protruding portion of each microbead 2905 can apply a force that isproportional to the spring constant of its corresponding spring 2903.

FIG. 29B illustrates a post-lamination process in which the microbeadsurface 2950 is walked slowly over the surface of a laminate 2907. Themotion can be automatic or manual. In this example, the surface of thelaminate 2907 has peaks 2909 and valleys 2911 as a result of, forexample, underlying conductive traces (not shown). As the microbeadsurface 2900 is moved across the surface, the microbeads can potentiallyprotrude down into a valley 2911 and push an air bubble 2913 to aperimeter of the laminate 2907, thereby preventing air bubbles frombeing trapped in the laminate 2907. In particular, the microbead surface2900 can be formed such that, for example, the sizes of the microbeads2905, the distances between the microbeads 2905, and/or the patterncreated by the microbead protrusion conform to an underlying conductivetrace pattern, potentially increasing the efficiency of thepost-lamination process. In one embodiment, the microbeads 2905 are 1 mmto 5 mm in size and are 4 mm to 10 mm apart.

FIG. 30 illustrates a substrate 3201 including perforations 3203.Perforations in either or both of the substrate 3201 and the flexiblematerial 3203 can help air bubbles escape.

As one skilled in the art would readily understand after reading thedisclosure herein, various aspects of the configuration of thelamination system can be adjusted to produce many different changes inthe pressure region during a lamination process. The aspects of theconfiguration include, but are not limited to, the size and shape of theupper and lower holders, the materials used in the holders, theadhesives used, the materials to be laminated together, the differentrotational motions, such as rolls, pitches and yaws, and varioustranslational motions along different axes, the use of multiple passes,and post-lamination processes. Furthermore, any of the foregoingprocesses that utilize a rigid lower holder and a rigid upper holder canbe used to laminate a rigid material to a rigid curved substrate. Inother words, in those example embodiments, and others that one skilledin the art would readily recognize, the material that is laminated to arigid curved substrate need not be flexible, but may be rigid.

In addition, any of the foregoing processes may be applied in a vacuumchamber or in ambient pressure. A compliant or spring-supported layermay be added to any of the holders not explicitly listed as compliant,particularly as a method of uniformly distributing applied forces acrossthe substrates. Also, adjustment for alignment in axes other than thez-axis (lateral dimensions x and y, as well as yaw, pitch and roll) maybe added to one or both the lower and the upper holders, particularly tofacilitate alignment. Lamination by any of the foregoing methods may befollowed by an autoclave process, in which individual parts may or maynot be placed in vacuum bags, to increase bond quality and reducetrapped bubbles. In addition, alignment pins as shown in the figures donot represent all possible locations or configurations of alignmentfeatures. Fiducials and optically assisted alignment are also supportedin the forgoing processes.

Although embodiments of this invention have been fully described withreference to the accompanying drawings, it is to be noted that variouschanges and modifications will become apparent to those skilled in theart. Such changes and modifications are to be understood as beingincluded within the scope of embodiments of this invention as defined bythe appended claims.

1. An apparatus for laminating a surface of a flexible material to asurface of a curved material, the apparatus comprising: a first holderconfigured for contacting the flexible material; a second holderconfigured for contacting the curved material; a support holder having aplurality of alignment pins for supporting the flexible material as aflat surface spaced apart from a contact surface of the first holder andthe curved material; a pressure applying device configured for pressingthe first holder against the flexible material to cause the flexiblematerial to press against the curved material at a first portion of theflexible material at a pressure region between the surface of theflexible material and the surface of the curved material; articulationmeans for shifting the first holder across the flexible member, thearticulation means causing translation of the first holder along both anx and y direction while moving the first holder toward the second holderalong a z direction, thus changing at least the position of the pressureregion to laminate the flexible material to the curved material andremove air bubbles between the laminated flexible material and thecurved material.
 2. The apparatus of claim 1, wherein the flexiblematerial is a substantially planar circuit board.
 3. The apparatus ofclaim 1, wherein the flexible material comprises a plurality ofconductive traces on its surface and an insulating layer deposited overthe conductive traces.
 4. The apparatus of claim 1, wherein thelaminated flexible material and the curved material are a part of asensor array, and the sensor array is a part of a multi-touch mouse. 5.The apparatus of claim 1, further comprising an adhesive adapted tolaminate the flexible material and the curved material, the adhesiveselected from a group consisting of pressure-sensitive adhesives (PSAs),re-workable PSAs, thermoplastic film, thermoset film, thermal cureliquid, UV curing liquid, and multiple-component adhesives.
 6. Theapparatus of claim 1, wherein the support holder is part of the secondholder.
 7. The apparatus of claim 1, wherein the first holder is made ofa deformable material.
 8. The apparatus of claim 1, wherein the pressureapplying device is adapted to change an amount of pressure applied tothe surface of the flexible material and the surface of the curvedmaterial.
 9. The apparatus of claim 1, wherein the change of thepressure region is in response to a shape of at least one of the firstholder and the second holder.
 10. The apparatus of claim 1, wherein thearticulation means comprising a gimbal adapted to control movement ofthe first holder and create a rolling motion of the first holder. 11.The apparatus of claim 1, further comprising a microbead surface adaptedto be walked over the flexible material to remove air bubbles betweenthe laminated flexible material and the curved material.
 12. Theapparatus of claim 11, wherein the flexible material has a conductivetrace pattern and microbeads on the microbead surface have a size andspacing to conform to the conductive trace pattern.
 13. The apparatus ofclaim 12, wherein the conductive trace pattern has a plurality of peaksand valleys and the microbeads protrude into the valleys to push air toa perimeter of the laminated flexible material and the curved materialduring walking.
 14. The apparatus of claim 1, wherein break away tabssecure the flexible material to the alignment pins, the break away tabsconfigured to detach the flexible material from the alignment pins underpressure.
 15. The apparatus of claim 14, further comprising a microbeadsurface adapted to be walked over the flexible material to remove airbubbles between the laminated flexible material and the curved material.16. The apparatus of claim 15, wherein the flexible material has aconductive trace pattern and microbeads on the microbead surface have asize and spacing to conform to the conductive trace pattern.
 17. Theapparatus of claim 16, wherein the conductive trace pattern has aplurality of peaks and valleys and the microbeads protrude into thevalleys to push air to a perimeter of the laminate during walking.